Carbureting apparatus



Aug. 15, 1939. I

R. F. ENslGN CABBURETING APPARATUS- Filed Sept. 26, 1936 5 Sheets-Sheetl Aug. l5, 1939.

R. F. ENSIGN CABBURETING APPARATUS Filed Sept. 26, 1936 `3 Sheets-Sheet2 Aug- 15, 1939- R. F. ENslGN 2,169,487

CABBURETING APPARATUS agorney Patented Aug. 15, 19,39

UNITED STATES CARBURETING APPARATUS Roy F. Ensign, San Marino, Calif.,assignor to Ensign Carburetor Co., Ltd., Huntington Park, Calif., acorporation of California Application september 26, 193s, serial No.102,718

7 Claims.

This invention pertains generally to fuel feeding and carburetingapparatus for internal combustion engines, and in one of its more specicmajor aspects deals with Aapparatus for supplying engines with gaseousfuel at substantially constant pressure and at variable rates inconformity with the requirements of the engine under differentconditions of operation. The invention also contemplates the provisionof a carbureting apparatus which may operate selectively on eithergaseous or liquid fuel.

With particular reference to that aspect of the invention dealing withthe supply of and carburetion with natural gas or other forms of gas forthe operation of internal combustion engines, my objects, generally, arethreefold: First, to regulate the pressure of the gas fed to thecarbureter so as to maintain substantially constant pressure under allloads, preferably a pressure close to or slightly under atmosphericpressure; second, to produce the correct mixture of gas and air for theengine under all speed and load conditions; and third, to make itpossible to obtain a perfect mixture during cranking of the engine andinitial operation up to the point where normal operating conditionsobtain, The latter object is particularly stressed because of thediiculties heretofore involved in starting. In order that a morecomprehensive understanding of the difficulties which are overcome bythe invention may be had at the outset, it may be Well to refer brieflyto the conditions giving rise to the problem and how, in general, theinvention provides the solution.

In order to obtain the required volume of mixture to meet the powerrequirements with a gas carbureter the venturi must necessarily berelatively large and consequently the fuel metering depression thereinat cranking or idling speeds is not sufcient to .give a continuousproper proportioning of the fuel and air mixture. In accordance with theinvention, I overcome this difilculty by providing means whereby duringcranking or idling speeds, the engine may be supplied with the correctamount of gaseous fuel without having to depend on the normal Venturidepression at these speeds, thereby overcoming the above mentioneddifculties.

The present gas carbureting apparatus is generally similar to thatdescribed in a copending application, Ser. No. 26,768, led June 15, 1935by O. H. Ensign on Gas pressure regulator, now Patent No. 2,073,298,March 9, 1937, but dilers essentially with reference to the means forobtaining proper fuel mixtures at starting and idling speeds. I'he O. H.Ensign application embodies generally the combination of a differentialgas pressure regulator and gas carbureter, and in that apparatus anamount of gas flow to the carbureter sufficient for starting purposes isproduced by a manually operated priming device causing the pressureregulator to deliver gas independently of pressure conditions in thesuction passage of the carbureter. While that type of priming device hasproven satisfactory in many different types of installations, in othersit has to some extent proved less efficient than the corresponding meansembodied in the present invention, due to the fact that where thecarbureter includes pipe connections to an air cleaner, theseconnections and the cleaner itself become filled with gas at starting,excluding the air and requiring considerable cranking to thin the fueland air mixture being taken into the engine to the desired ratio atengine starting speed. Theoretically, of course, it would be possible toprime the regulator just sufficiently to deliver the correct amount ofgas, but in practice such exactness of control is difficult, and usuallythe result is that, where the engine is cold, combustion occursirregularly because the improperly proportioned fuel mixture does nothave suicient energy upon combustion to shear the oil lms on thecylinder walls and to continue to operate the engine while it is stillcold.

Viewed in one aspect, the invention may be regarded as providing for twostage carburetion to supply a combustible mixture of the properproportions lrst at starting speeds,4 and then as the engine warms up,for normal operating speed. Briefly, the rst stage carburetion isaccomplished by providing within the suction passage of the carbureter amanually operated valve, independent of the throttle, which obstructsthe suction passage and thereby creates a depression which causes thegas to ow from the regulator, such gas being delivered to the suctionpassage at the inlet side of the throttle through a severely restrictedopening which is, in effect, imposed in the path of flow simultaneouslywith the operation of the valve. The second stage carburetion iseffected by relieving the suction passage of the obstruction imposed bythe said manually operated valve and by delivering to the suctionpassagea ow of gas under control of the throttle which is properlyrestricted for the normal oper- 'ating requirements.

It is also an object of the invention to provide a carbureter capable ofoperating on either liquid or gaseous fuel. In accomplishing this objectI A2 A YProvideseparate nqid'ndgasmeln 'l charging into the suctionpassage of the carbureter at the inlet side of the throttle, a suitablefuel feeding system for supplying liquid fuel from a constant levelsupply chamber to the liquid fuel nozzle, a pressure regulator forSupplying gaseous fuel at substantially constant pressure to the gasfuel nozzle, separate controls wherebyv the carbureter may operateselectively on liquid or gaseous fuel.

In this latter connection the invention contemplates as a furtherobject, the provision of a float locking mechanism which will preventwear in the parts when the carbureteris being operated on gas and theliquid supply unit is shut off.

Relative to the combination gas and liquid carbureter, my invention alsocontemplates gas feeding attachment which can readily be mounted on astandard liquid fuel carbureter to convert the same to a combinationunit adapted for operation with either liquid or gaseous fuel All theabove mentioned features and objects of the invention, as well asfurther aspects and def tails thereof, will be best understood from thenism and showing the shutter valve in normal .operating position;

Fig. 3 is an end view of the air intake'illustrating the choke valveconstruction contemplated by this invention; i

Fig, 4 is a fragmentary section on line 4-4 of Fig.v 5 is a viewgenerally similar to Fig. 1, showing a combined gasoline and gascarbureter. the y gas pressure regulator being shown in elevation;

Fig. 6 is a sectional view showing a variational form of carbureteradapted to operate on either gasoline or gas;

Fig. 7 is a section on line 1--1 of Fig. 6;

Fig. 'la is a fragmentary section on the line laf-1a of Fig, 6; p

Figs. 8 and 9 are fragmentary sections on lines 8-8 and 9-9 of Fig. 6;

Fig. 10 is a fragmentary section on the line III-I0 of Fig. 9; and yFig. 11 is a diagrammatic view illustrating means for simultaneouslyactuating the gas and liquid .control valves in a combination unit sothat the selective supply of gaseous and liquid fuels is automaticallycontrolled,

In Fig', 1 I show a gas fuel supply system comprising a pressureregulator, generally indicated at I0 for feeding gas at substantiallyconstant, and preferably subatmospheric pressure, to the carbureter .II. It will be understood that in its broad aspects, the invention is notlimited to the use of a pressure regulator or carbureter of anyparticular construction, or` built according to the details shown inFig. l, but that any suitable regulator and carbureter combination, maybe used so long as they contain parts in the operative relationshipsspecified in the claims.V The particular apparatus illustrated hashowever, been found especially suited to the purposes of the invention',and hence may be regard-ed as representing a preferred construction.

I have illustrated a simple form comprising a suction or fuel and airmixing passage composed of sections I2 and I3 connected together byscrews I4, section I2 being attached to the engine manifold fuel and airintake I5. A venturi I6 is placed in the suction passage be- 4twenfthe4inlet l1 and outlet Is, a mam fuel nozzle I9 discharging into `thethroat of the venturi under control of the usual throttle 20. Furtherdetails of the carbureter will be later 'described in connection withtheir operative relationships with thev pressure regulator I0.

`For amorecomplete` discussion of the operation of pressure regulatorI0, reference may be had to the patent of O. H. Ensign, referred tohereinabove, anda relatively brief description of the regulator detailsand operation will suillce for present purposes. The regulator bodycomprises Vthree sections 2I, 22 and 23 between which are clamped themain and pilot diaphragms 24 and 25.' Pressure chambers 26 and 21 areprovided Y below and above main diaphragm 24, the last mentioned chamberbeing defined by a transverse wall 28 within the intermediatebody'section 22.

Chamber 29 above the pilot diaphragm 25, constitutes a referencepressure chamber whereby at all times a relatively constant pressure isap` plied to the upper surface of the diaphragm. The chamber 30, belowthe diaphragm, which is proof carbureter vided with a partition plate 3Iheld in place by an expansible. lock ring 32, constitutes a variablepressure chamber,

High pressure gas supplied to the regulator from inlet 33 is deflectedby a baille 34 into chamber 26, from whence it passes under control ofthe main regulator, valve 35 to the regulator outlet 36. The latterconnects by way of pipe 31 with a fuel supplypassage 38 formed withinsection I3 of the carbureter, the gas flowing from passage 38 undercontrol of the mechanism, (to be described hereinafter) to nozzle I9 viapassage 38. Main regulator valve 35 is attached to the main diaphragm 24byy lock ring 40 retaining the flanged head 4I of the valve stem 42within a connecting member 43 fastened to the diaphragm. Upward movementof the diaphragm is resisted iby 'springs attached to the diaphragm andatmospheric pressure, and, by reason of the regulator being operated bysuction communicated from the carbureter, will automatically shut offthe gas supply to the carbureter as soon as such suction is discontinuedwhen the engine stops.

A restricted iiow of gas is permitted from the inlet 33 to chamber 21above the main diaphragm by way of bushing 45 having a small calibratedorifice, and passage 46, these passages normally serving to balance thepressures applied to the'.

opposite sides of the main diaphragm. In order to avoid or dampen outexcessive'vibrations of the main diaphragm with resultant irregularitiesin the movement of valve 35 and in the outlet n pressure, chamber 21 isplaced in communication with a closed chamber 41 via orifice 48.

The operation of the main diaphragm 24 and the consequent actuation ofthe valve 35 was discussed in detail in connection with Fig. 4 of thecopending O. H. Ensign patent herein- -above referred to. It suflices tosay that when a positive suction is established in the fuel supplypassage 38 that such suction is communicated through connections 3l and36 and the passage indicated at 50-50 into the variable pressure chamber30 below the pilot diaphragm 25 by way of a port 5|. Port 5| is arestricted port and is located between the pilot diaphragm 25 and theplate 3|. In addition to this port 5| the variable pressure chamber isprovided with a substantially unrestricted port indicated at 52, suchport is located'beneath the plate 3| and also communicates with thepassage 50--50'.

The suction thus communicated to the variable pressure chamber 30establishes a pressure differential between the two sides of the pilotdiaphragm 25, such differential being effective to depress thisdiaphragm. When the pilot diaphragm 25 is thus depressed, it iseffective to actuate the pilot valve mechanism generally indicated byreference numeral 53, structural details of which are also fullydescribed in the copending O. H. Ensign patent hereinabove referred to.The minimum depression which will actuate the regulator to deliver gastherefrom is set by the size and compression valve of the spring 53 inthe valve mechanism 53. The opening of the pilot valve 53 under theaction of a depression in chamber 30 communicates the suction from thelower part of chamber to chamber 2l at the upper side of the maindiaphragm 23, causing such diaphragm to be elevated with the result thatthe main valve 35 is opened.

in order to accommodate for any pressure fluctuations at the air intake,which may occur due to the use of air cleaners or otherdevices, and to.maintain a uniform pressure balance in the carbureting system at alltimes, it is preferable that the reference pressure chamber 29 above thepilot diaphragm 25 be connected to the air inlet passage il rather thanbeing opened to the atmosphere. For the purpose of establishing thispressure communication, the section 23 above the pilot diaphragm isshown as being formed with a passage 55 which is connected through atting 56 and a tubing 57 with a pilot tube 58 which extends into theinlet end of the air passage.

For proper idling operation it is important that a positive suction becommunicated to the variable pressure chamber 30 during such idlingoperations. This suction must be of suficient magnitude to hold the mainvalve 35 open the required amount to supply gas for a proper combustionmixture and is obtained by establishing a communication between thevariable pressure chamber 30 and a region of the air intake passagebeyond the throttle in or adjacent an engine manifold connection l5. Forthis purpose, the carburetor section l2 is provided with a wall passage60 which communicates with the main air passage through a controlorifice 5|. The passage 6D is connected through the fittings generallyindicated at 52 with an adjusting screw chamber 53 on the top section 23of the regulator. This adjusting screw or adjusting valve chamber 53 isequipped with a needle valve 56 which communicates with a horizontalchamber 55, such chamber opening into the top of passage 50 which hasthe ports 5| and 52 therein communicating with the variable pressurechamber. With this arrangement, it will be seen that on closing down thethrottle to the correct idling speed, the regulated suction through 6|,60 and 62 to the valve 64 and through such valve to the variablepressure chamber 30 causes the pilot diaphragm to lower just the correctamount to supply the idle fuel. Such an arrangement is important in aregulator of this character, due to the fact that, with the full sizeventuri required for maximum power, the amount of gas drawn through thenozzle I9 when idling with the choke wide open is'not easily regulated.

Through the use of the passages and connections just described, aportion of the idle suction is transferred to the under side of thepilot diaphragm and is bled by the passages 50 and 50' which compensatefor the violent suction above the orifice 6|. The foregoing is also setout in said O. H. Ensign patent.

As has been previously pointed out it is one of the principal objects ofthis invention to provide a gas carbureter of the general characterdescribed above with means for supplying a combustible mixture of theproper proportions during cranking or starting speeds. For thesatisfaction of this object, my invention contemplates the provision ofa choke valve 68 which is shown as comprising a conventional disk valvemounted across the intake end of the air passage upon a shaft 69, theouter end of which is equipped with a levermember 'l0 for its manualactuation. The choke disk 68 is shown as being provided with an airorifice '|2. 'When the valve 68 is closed, as is done during crankingoperation, the suction created at this speed is sufficient to draw arelatively small volume of air through the orilce 12.

In order that the Yproper amount of gas may be supplied to the airintake passage while the choke is closed and the air is being drawnthrough the restricted orifice '|2, it is important that the ow passagefor the gas between the chamber 38 and the main air passage be likewiserestricted. The restriction of the gas ow may be accomplished in variousways, but it is important for more satisfactory operation, that therestriction employed here be made adjustable to accommodate fordifferent` types of fuel. In the form of my invention, which is shown inFigs. l and 2, this is accomplished by completely cutting 01T the inletopening to chamber, 39 through the medium of a shutter valve generallyindicated at 74, which in effect interposes a relatively severelyrestricted orifice 'l5 as the only passage between the chamber 38 andthe interior of chamber 39. The orifice l5, which may be termed astarting orifice, is equipped or associated with a needle valve 716adjustable to control the flow therethrough. And while the passage 39may have been referred to herein as a relatively unrestricted passage,it will be understood that an adjustable restriction is provided for thepurpose of controlling the flow of gas therethrough. This last mentionedrestriction is shown as comprising an adjustable valve member generallyindicated by reference numeral (see Fig. 2).

The shutter valve 'i4 is shown as comprising an elongated plate slottedas indicated at 80 and supported by a pivot 8|, which extends throughthe slot. The plate ld is biased upwardly toward the seating surfacesurrounding the bottom of passage 39, by means of a compression spring52, supported by a washer 83 and a key 84 in me bottom f the pivot pinal. This valve u must be actuated simultaneously with the openinglandclosing movements of the choke valve 5l' and i'or the purpose ofeffecting such movement, the choke shaft 69 is equipped with a collar85, which carries a pin 86, such pin engaging in an opening 81 in vvalveplate 14.

For the purpose of holding the valve plate 14 in its two extremepositions of adjustment, illustrated in full lines and dotted lines inFig. 2, a compression spring is interposed in the slot 80 between thepivot pin 8| and the rear end of the slot. a

During starting operations the choke'68 is closed manually by means ofthe lever 10, such operation placing the shutter valve 14 over the lowerend of the gas nozzle chamber 39, thereby closingthe same. The throttleis' then opened to about the position shown in Fig. 1 and upon crankingthe engine there will be a positive suction of air through the orifice12 and of gas through the orifice 15. The suction thus supplied in thegas chamber 38 will be positively communicated to passages 50--50 andthrough the port 5| to the under side of the rpilot diaphragm 25. Thissuction, applied in the variable pressure chamber below the pilotdiaphragm, will depress the diaphragm and consequently actuate the pilotvalve to ultimately open the main valve 25 in the manner previouslydescribed thereby supplying gas for the operation of the engine.

As soon as the engine has turned over for av short period, the chokelever 10 is turned to immediately throw the choke valve 68 into its openposition, it being preferred that no intermediate position be used. Theopening of the choke valve 68 simultaneously opens the shutter valve 14so that gas is then delivered to the air passage directly through thebottom openingof chamber 39 in which the valve 11 has been properlyadjusted for normal operating conditions.

It has been previously pointed out as an additional object of thisinvention, to provide a carbureter capable of operating on either liquidor from the regulator, generally indicated by reference numeral |011..The regulator is supplied with gas 'through a valve indicated byreference numeral 33a, which may be sel'ectivelyopened or closed tosupply the carbureter with gas or liquid fuel as may be demanded by theparticular l operating conditions. N The'regulator is the same as thatshown at I0 in Fig. l, and for that reason is illustrated in outsideelevation.

Gas is supplied tothe throat of the venturi |6a through a gas tube |9a,mounted in a gas chamber 39a, such chamber incorporating a shutter valve14a, which is operated in conjunction with the choke valve 68a in thesame manner as was described in connection with Fig. l. The regulator isalso equipped with a gas pressure balance connection, generallyindicated by reference numeral 51a and an idling connection generallyindicated by reference numeral 62a.

liquid fuel la supplied to the throat of the venturi'through a jet 89from a constant level.

intake 9| in the fuel chamber housing into the fuel chamber itself, iscontrolled by suitable valve means as indicated at 92, such valve meansbeing of conventional construction, and being actuated by a float lever93, which carries a float 93 on its free end, and is pivoted in thehousing'as indicated at 94.

The present form of liquid fuel supply unit for the combination gas andliquid carbureter shown in Fig. 5, is illustrated merely "for thepurpose of describing my invention, and is the same as that disclosedland described in the P. W. Ensign patent, No. 1,863,195, issued on June14, 1932, and for a detaileddescription of this liquid fuel sup-` plyunit, reference is made to that patent. Fork the purpose of describingthe present invention, it will be sufficient to point out that thesection |2a, which contains the venturi of the air passage, alsoincludes the idling by-pass, accelerating well, etc., indicated byreference numeral 95, The liquid fuel chamber 90 contains a block 96which includes primarily the ports and passages for controlling theinitial metering of the liquid fuel from the supply reservoir to themain fuel passage 91, which communicates with the jet 89.

The space above the liquid level in fuel reservoir 90 is closed againstdirect communication with the atmosphere, and suitable means is providedwhereby the pressure in the air intake |1a is applied to the fuel in thereservoir. In this embodiment of my invention, the inlet pressure iscommunicated to the fuel reservoir by a passage comprising an annularchamber |00, which surrounds the upper end of the elbow section l|311.The annular chamber |00 communicates with the inlet |1a of the main airpassage, through a'substantially unrestricted passage indicated at |0|,the passage 0| having an opening in the air passage |1a on the intakeside of the choke valve 68a. The annular chamber |00 communicates withthe fuel chamber above the liquid level therein through a passage shownin dotted lines at |02 and a port |02'.

Fuel is taken from the reservoir into a vertical riser passage |03 inblock 96, such passage comprising ay portion of the main fuel passage,by way of a valve controlled orifice |04 in the end of plug |05, whichis screwed into a bore within the bottom of the block. The flow throughthe orifice |04 is controlled throughk the medium of a needle valve |05,which is urged upward into engagement with a screw cap |06 by means of aspring |01 confined between the upper face of the block and a ange |08on the upper end of the valve. The fuel admitted to the riser passage|03 through the valve controlled orifice flows upwardly and over thelower edge of an unrestricted opening ||0 into passage and from thereitpasses downwardly to the horizontal main fuel passage 91. A restrictedflow of air is also taken into the passage l|03 through a calibratedbushing ||I3 at its upper end, the fuel and air being mixed in flowingthrough the openy ing and the mixture is conducted downeration of theliquid unit of this combination carbureter, reference is again made tothe P. W. Ensign patent hereinabove referred to, and at this time it isagain emphasized that my invention does not contemplate or require theuse of any specic liquid fuel supply unit. Asa matter of fact, it is animportant and novel feature of the invention that the gas supply unitdescribed above may be employed as an attachment for a conventionalliquid carbureter to convert the same to a combination unit. In thisregard, my invention contemplates the replacement of the air intakesection of a conventional liquid fuel carbureter with a sectioncorresponding to the elbow I3 or |3a, which has a gas supply passageformed of a length such that its outlet opens substantially in thethroatportion of the venturi.

In a combination carbureter of this character, it is important thatmeans be provided for avoid- 'ing undue wear in the parts of the liquidunit of the carbureter when the carbureter is being operated with gasfuel. It is also important that means be provided for shutting 01T theliquid unit so that the combination carbureter can be selectivelyoperated on gas or liquid, such carbureter being provided with a valvefor shutting oi the gas supply indicated at 33a, referred tohereinabove. For the purpose of shutting off the liquid supply unit andfurther to lock the float and the float control valve against vibrationwhen the liquid fuel supply unit is shut ofi, I employ a float lockingmechanism, generally indicated by reference numeral |20. This mechanismembodies a bushing |2l, threaded into a suitably formed boss |22 on theliquid fuel chamber housing 90, such bushing being internally threadedto receive a threaded adjusting stem 12d which is equipped with a thumbnut |25. The upper end of this adjusting stem bears against a plungermember |26, which carries a compression spring |21, engaging the undersurface of the oat lever 03 at its upper end. It will be seen that theadjusting screw |24 may be advanced upwardly in its threads to raise theoat lever into a position where it will lock the valve 92 in closedposition, the spring |21 being compressed under this action to lock thefloat against vibration when the valve 92 is thus closed. In the formdescribed above, the gas control valve and the liquid control mechanismare illustrated as being independently operated. It may be preferableunder some conditions of operation to interconnect the gas and liquidcontrols so that the one is automatically shut oil when the other isopened; one fom of such connection is diagrammatically illustrated inFig. l1 and will be referred to in detail later in the description.

In Figs. 6 to 10, inclusive, I have shown another modified form of acombination gas and liquid carbureter of the special down-draft type. Inthis connection it should be understood that the forms as shown in Figs.l and 5 can be used either down-draft or up-draft by simply turning thewhole carbureter element over. Referring to Fig. 6, the main air passageis shown as being comprised of sections |30, |3| and |32, the throttlevalve indicated by numeral 20h, being located in section |32, and thechoke Valve 68h being situated in the section |30.

The gas passage 31h leading from a regulator similar to that shown inFig. 5, communicates with a cylindrical valve chamber |34, whichcontains a cylindrical valve |35, attached to the choke shaft 69h. Thiscylindrical valve |35 is cut away on one side, as indicated at |31, toprovide an opening which normally leads to the gas inlet chamber|38-|38'. The portion |38 of this chamber has an opening |39communicating with the throat of the venturi |6b, and contains a screwvalve |40 for restricting the gas flow, the required amount for normaloperating condition.

The choke valve 68h is providedwith' an orifice 12b, and when the chokevalve is closed, it will be seen that the air is drawn into'the suctionpassage through this orifice. Simultaneously with the closure of thechoke valve 68h, it will also be seen that the skirt portion of thecylindrical valve |34 rotates around to close the passage leading to thegas supply chamber |38. The closure of the main opening in passage |38in this manner, in effect interposes between the connection 31h and thepassage or chamber |38-|38' a restricted passage indicated generally byreference numeral 15b.

'I'he passage 15b, as shown in Figs. 7 and '70, embodies a controlchamber |43, communicating with chamber |38 through a port |43', thecontrol chamber |43 being in communication with the connection 31hthrough a passage |44-|44. The control chamber |43 carries a needlevalve generally indicated by reference numeral |45, which is employed tocontrol the restricted oW of gas through the restricted passage 15bduring starting operations, such needle valve adjustment correspondingto the adjustment shown in connection with the valve 16 in Fig. 2.

In this embodiment of my invention, a Pitot tube 58h enters the intakeconnection 11b on the inlet side of the choke valve 68h and connectsthrough pipe 59h to the upper side of the diaphragm in a suitableregulator, similar to that shown in Fig. 5, for the purpose ofmaintaining a pressure balance on the pilot diaphragm in the mannerdescribed in connection with Fig. 1.

The idle opening @Ib is connected through a connection 62h to idleadjustment valve means similar to that indicated at 63 in Fig. l.

The liquid supply unit for the carbureter is shown as comprising in ageneral way, a float chamber portion |50 cast on one side of the section13|. In this portion |50 is assembled the liquid or gasoline carbureterparts. A oat |5I is attached to a iloat lever |52 pivoted at |53 andadapted to close the oat valve, indicated generally by reference numeral|54. Fuel enters the connection |56 through the passage |55, and howsthrough the openings |56 to the valve seat.

The liquid fuel flows from the float chamber |53 through a fuel orice|60, which is equipped with an adjustable needle valve 6| forcontrolling the ow therethrough. Needle |6| is adjusted by operating themilled head |62, such head being associated with a spring 4|63interposed between the under side of the head and the top of theadjustment needle.

Fuel flowing through the orice |60 enters the chamber |65, and fromthere passes through the riser passage |66 and the fuel nozzle |61 intothe air stream passing through the venturi |6b.

The liquid unit is equipped with a riser passage (best illustrated inFig. 9) which embodies a tube |10, and passages |`l| and |12, the tube|10 being restricted as indicated at 13. The tube |10 takes out of thewell chamber |65 at its lower end, thus drawing up the fuel to thechamber |11 which is provided with an air vent |15, equipped with anadjusting screw valve |16. The leg |12 of the idle passage terminates ina chamber |11 which, as illustrated in Fig. 10, communicatesV Aneconomizer passage |80 connects from thev air in-the upper portion ofthe float chamber to a chamber |8I, which has a bore |82 connecting withthe throttle tube at a point above the edgev ofthe throttle disk when itis in its closed position. This economizer operates to cause a` slightYdepression on the surface of the gasoline in the float chamber overthat portion-of the load which may be under throttle control, beginningslightly above idle.

For the purpose of locking the vibration, and to also lock the floatcontrol valve in closed position when the carbureter is being operatedon gas alone, I provide an adjusting screw |90, which is shown as beingvmounted in a bushing mounting |9|, -such screw carryingl a compressionspring |92 and a plunger |93, which contacts a cross member |94 on thefloat lever mechanism below the lower end |54f ofthe iloat` valve. Withthis arrangement it will be-seen that the float and float valve may belocked in avalve closing position, so that there is no wear intheseparts due to vibration of the engine vwhile-the v" "delivering gas at'substantially constant pressure Y to said suction passage, said gasdelivery meansl including a'relatively severely restricted startingcarbureter is being operatedwith gas alone,"v

A pressure balance is maintained on top of the liquid in the floatchamber through a passage," such passage `opening into the top of thefioat chamber and having a port |91 c :on'imunicat'ing- 'with the airinlet portiony of thesi'lctionpassage!' As was previously stated inconnection with.v Fig. 5, my invention contemplatesthe `p'ro's'fision'of means for interconnecting the gas inl'etcon'- trol valve 33a and thefloat and float valve lock'- ing mechanism |20 so that when oneconnectionis opened the other is automatically closed: 'n. Fig. 11, Ihave shown one form of vconnection which may be employed forthis'purpose. In this.

construction the gas inlet connection 33e is shown as being equippedwith a disk va1ve`200 mounted on a shaft 20|, the extending endv ofwhich carries a lever 202.- The float lever 93c and the valve 92e areadapted to be urged upwardly into a locked position by a plunger member203, which is slidably mounted through suitable packing means inabushing |2|c. The bottom of the plunger 203 `is attached to a bell crank200, pivoted on a suitable bracket as indicated at 205. The other arm ofthe bell crank 204 is attached by means of a link 206 to the lever 202.

A tension spring 201 is provided for the purpose of urging th'e linkagesystem to one` of its extreme positions. In the form shown, the spring201 holds the'gas valve 200 closed and depresses the plunger l203 sothat the float and oat valve are free to operate. An operating link orrod 209 is provided for controlling the position of these two valvemeans. Thus when it is desired to operate on gas, the rod 209` is drawnforward in the direction of thev arrow A to open the gas valve 200 andlock the float valve. Suitable latching means 2|0-2|| may be providedfor locking ,the rod 209 in this latter position.. When thev latch2|0-2II is released the valve and float locking mechanism are drawn backto the other extreme position (shown inl full lines) by the action ofthe spring 201.

It is to be understood that while I'have here described and illustratedcertain preferred emy float against limited to the precise details ofconstructionor theparticular 'combination of parts described above, Abutincludes within its scope whatever reter including a suction passageconnecting with an engine manifold and having an air inlet, an outletand a throttle for controlling the flow of iluids through saidsuctionpassage; means for f' delivering gas atvsubstantially constant pressureto saidsuction passage, said gas delivery means including a relativelyseverely restricted starting orifice and a relatively less restrictednormal operating' orifice; a choke valve in said suction I passage atthe inlet side of the 'point of fuel discharge from said fuel deliveryorices; means for closing said choke valve; a fuel controly valveactuated with saidchoke valve for closing said normal operating orifice;and means for admitting a restricted flow of air to said suction passagewhen said choke valve is closed.

-2. The combination comprising: a gas carbureter including a suctionpassage connecting with an engine manifold and having an air inlet, anoutlet and a throttle for controlling the flow of fluids through saidsuction passage; means for orifice and a relatively less restrictednormal operating orifice; a choke valve in said suctionpaslvalveaLctuated with said choke valve for closing said normaloperating orifice.

l3. The combination comprising: a gas carbureter including a suctionpassage connecting withv an engine manifold and having an air inlet, an

outlet and a throttle for controlling the flow of iluids through saidsuction passage; a pressure v regulator having a gas intake and anoutlet communicating with said suction passage, said regulator operatingto deliver gas to the carbureter at substantially constant pressure,said regulator outlet being communicable with said suction passage byway vof a fuel delivery passage; a choke valve in the suction passageatthe inlet side of the point of fuel discharge from said fuel deliverypassage; a fuel control valve operated in accordance with movements ofsaid choke valve to control the ilow of fuel through said deliverypassage, saidfuel control valve closing said delivery pas-- sage whensaid choke valve is in closed position; and means for delivering to saidsuction passage at the outlet side of the choke valve, a restricted flowof fuel when said fuel control valve is in closed position. 1

4. The combination comprising, a gas carbureter including a suctionpassage connecting with an engine manifold and having an air inlet,anoutlet and a throttle for controlling the flow of fluids through saidsuction passage; a pressure regulator having a gas intake and an outletcommunieating Withsaid suction passage, said regulator operating vtodeliver gas to the carbureter at vsubstantially constant pressure, saidregulator outlet being communicablewith said suction passage by way of afuel delivery passage; a choke vvalve in the suction passage at theinlet side of the point of fuel discharge from said fuel deliverypassage; a fuel control valve operated in accordance with movements ofsaid choke valve to control the iiow of fuel through said deliverypassage, said fuel control valve closing said delivery passage when saidchoke valve is in closed position; and means for delivering to saidsuction passage at the outlet side of the choke valve, a restricted flowof fuel when said fuel control valve is in closed position, said chokevalve having a relatively small air passing opening.

5. The combination comprising; a gas carbureter including a suctionpassage connecting with an engine manifold and having an air inlet, anoutlet and a throttle for controlling the flow of fluids through saidsuction passage; a venturi at the inlet side of the' throttle; apressure regulator having a gas intake and an outlet communicating withsaid suction passage, said regulator operating to deliver gas to thecarbureter at substantially constant pressure; a fuel nozzle discharginginto said venturi, said nozzle being communicable with said regulatoroutlet by way of a fuel delivery passage; a choke valve in the suctionpassage at the inlet side of said venturi; a valve operated inaccordance with the movements of said choke valve to control the ow offuel through said delivery passage; and means for delivery to saidsuction passage at the outlet side of the choke valve a restricted flowof fuel when said fuel uids through said suction passage; a pressureregulator having a gas intake and an outlet communicating with saidsuction passagesaid regulator outlet being communicable with saidsuction passage by way of a fuel delivery passage; a choke valve in thesuction passage at the vinlet side of the point of fuel discharge fromsaid fuel delivery passage; a fuel control valve operated in accordancewith movements of said choke valve to control the flow of fuel throughsaid delivery passage, and means for delivering to said suction passagea restricted flow of fuel when said fuel control valve is in closedposition.

7. The combination comprising: a gas carbureter including a suction;passage connecting with an engine manifold and having an air inlet, anoutlet and a throttle for controlling the flow of fluids through saidsuction passage; a pressure regulator having a gas intake and an outletcommunicating with said suction passage, said regulator operating todeliver gas to the carbureter at substantially constant pressure; a fuelnozzle in said passage; a manually operated choke at the inlet side ofsaid nozzle; means including a fuel passage for feeding gas to saidnozzle; a valve movable with said choke valve to control the flow of gasthrough.A said fuel passage, and means for feeding to said suctionpassage a restricted ilow of gas when the last mentioned valve is inclosed position.

ROY F. ENSIGN.

